Today I finally decided to upgrade our 3CX phone system from v11 beta to v11 SP3. I backed up the database, uninstalled the old version, installed the new and restored from a backup using the wizard. Everything appeared to install and restore properly, but when I factory reset a 504G, it would not auto provision using option 66 from the DHCP server. After further investigation, I found that the "<macaddress>.xml" files were missing from the server. I went into the extension settings in the management interface, clicked apply and received this error message: 3CX Interface An exception occurred EditExtension Error: The given key was not present in the dictionary. The error seems to happen regardless of the phone template I select (even using the generic templates). Furthermore, the "<macaddress>.xml" file never gets updated or created if the error occurs. Is there something I need to change in the template or settings to make it compatible with SP3? Thanks for your time.